Contact apparatus



Aug` 18, 1936- R. R. coLLlNs 2,051,545

CONTACT APPARATUS Aug. 18, 1936. R. R. coLLlNs CONTACT APPARATUS FiledApril 14, 1933 3 Sheets-Sheet 2 .i E n n-:1 r-1 Aug. 18,1936. R. R.COLLINS CONTACT APPARATUS Filed April 14, 1933 3 ShetS-'Sheet 3 poordistribution ofthe Patented A ug. 18, 1936 UNITED 's'rATEsPA'rENT OFFICE21,051,545 -CONTACT APPARATUS Raymann a. comm, Forest mus, N. Y..

to The Lummus Company,

assigner New York, N. Y., a

corporation of Delaware l Application April 14, 1933, Serial No. 666,144

The present invention relates 11 Claims.

to contact apparatus and .more particularlyto apparatus forpromotingliquid-to-liquid contact, as in liquld extraction process, orliquid-to-gas contact, as

in scrubbing and .rectifying processes.

In the usual forms of liquid extraction apparatus, the degree ofextraction is limited by the eiliciency of contact which is frequentlylow because of the formation of channels and the Even with the usualliquid across the column. expedients for promoting contact, such asRaschig rings, channeling is not completely prevented and uncontactedstreams may form throughout the length of the tower.

The object of the present invention is to provide an apparatusparticularly extraction processes and useful in liquid also suitable forgas-toliquid contact, in which eiective distribution of the fluidsacross the column is maintained, and in which undesirablel channeling ispractically avoided. To this end,

the present invention comprises the apparatus hereinafter' described andparticularly defined in the claims.

In the accompanying diagrammatic sectional drawings, Fig. 1 is aelevation of the preferred form of the invention; Fig. 2 is a section online 2-2 of Fig. 1; 3-3 of Fig.

view of a number of units; Fig.

of a portion of one of the units;

Fig. 3 is a section on line l; Fig. 4 is an enlarged sectional 5 is aside view Fig. 6 is a vertical sectional view of a modied unit; Fig. 7is a perspective view of still another modified form of the invention;

Fig. 8 is perspective view of a modification embodying a unitaryarrangement; and Fig. 9 is a View,

one of the units of Fig. 8.

The invention is herein scribed as embodied in a partly in section, of

illustrated and deliquid extraction apparatus particularly constructedfor a solvent method of separating naphthenic and paraftlnic oilcomponents from a lubricating stock.

some forms of the extraction process, the lubricating stock is passed incountercurrent to a single solvent which vhas selective dissolvingpowers for either the naphthenic or the parafflnic oil groups, whileanother process contemplates passing inv countercurrent two solventswhich have selective dissolving actions on the two oil groups, the oilfeed being then introduced into a mediate point of the countercurrentpath. The apparatus shown in Fig. 1 is particularly constructed for thepractice of the extraction operation of the second type involving theuse of two solvents.

The apparatus comprises a c olumn 8 having II) would be omitted, the`oil feed Y duced through one of the -zles.

at a mediate point a feed inlet I0 for introduction of the oil to besubjected to the extraction process. Near the bottom of the column is anI4 for introducing a heavier solvent having selective dissolving powerfor the naphthenic components. At the bottom is a draw-off I6 from whichis withdrawn the extracted naphthenic components in mixture with some ofboth solvents and at the top is a withdrawal pipe IB for removal of theextracted parafllnic components which are also associated with some ofboth solvents. A vent pipe 20 is provided at the top. In operation ofthe process, the heavy solvent introduced at Il descends, and thelighter solvent, introduced at I2, ascends through the column.` In asingle solvent process, the pipe would be intropipes I2 or I4, and thesolvent wouldl be introduced through the other pipe.

Between the inlets III and I2 there are arranged a plurality of contactunits, indicated generally at 22. of liquid collecting troughs 24arranged in rows across the column, the rows being staggered or offset,as shown in Fig. 1. Connected to the bottom of eachtrough are twoinclined perforated plates 26, the ends of which are immersed in troughsof the row next below, the construction forming a diamond-shapedarrangement of the plates. The plates are perforated, as shown in Fig.4. The material of the perforations may be struck out to form louversV28. Each trough is provided with a serrated overow edge shown in Fig.5, to permit substantially uniform overflow of liquid, regardless of anyslight failure to level the column exactly. The plates 3| of the bottomrow are imperforate, and adjacent plates converge to form narrowtransverse openings 32 in each of which is disposed a plurality ofnozzles 34. Above each nozzle is a deflector 36 for dispersing liquidflowing through the noz- The nozzles are all connected together by pipes38 which are connected tothe inlet pipe I2. At the top of the column,the pipe Il connects with a series of pipes 40 which distribute theheavy solvent into the troughs 2-l` of the uppermost row'. The feed pipeI0 is similarly connected with nozzles 42 disposed internally of theunits at a mediate section of the column.

' In operation, the light and heavy solvents are continuously introducedby the pipes I2 and Il The units comprise a plurality and the feed oilis introduced by the pipe I8. The entire column is filled with liquid.'Ihe heavy solvent flowing into the uppermost troughs 24 overflows andruns down the inclined plates I6. At the same time, lighter liquidpassing upwardly through the column goes through the perforations of theplates and contacts intimately with the descending heavy solvent. Inthis operation, the heavy solvent is denuded of its paraillnicconstituents and is enriched by naphthenic constituents extracted fromthe ascending stream. The heavy liquid finds its way to the troughs ofthe row next below, from which it overflows into the succeeding rows oftroughs. The action o f contact at the surfaces of the plates isenhanced by the fact that the ascending lighter solvent carries someparticles ofthe heavier material upwardly into the diamond-shaped areas,after which these heavier particles separate from the descending streamand descend directly into the troughs. A fairly turbulent conditionarises by which complete and effective contact between allparticles ofthe several liquids is assured. It will be observed that since theliquid collecting in the troughs is always heavier than that risingthrough the diamond-shaped areas, there is no opportunity for ,thelighter liquid to pass into troughs but, on the contrary, it is obligedto ascend and pass through the perforations, thereby promoting theturbulent contact of the liquids. lIn the lowermost row, the descendingliquid is caused to converge toward the nozzles 34, thereby promoting anal intimate contact which assures substantially complete removal of theremnant of paramnic constituents. 'Ihe bottom of the column is providedwith an enlarged settling chamber 44 in which opportunity is affordedfor segregation of the material into layers, the lower layer beingwithdrawn at I8. Similarly, the upper section of the'column is providedwith an enlarged separating chamber 46 to permit segregation of theextracted parafnic oils from any heavier components which may tend torise toward the top of the column.

It will be observed that neither vthe descending nor the ascendingliquid is permitted to pass in any well-defined inactive channelsthrough the column. 'I'he descending liquid divides at each trough intotwo streams and accordingly, there is a definite transverse motion ofthe liquid across the column. Similarly, the ascending liquid is dividedinto two streams within each diamond-shaped area. Thorough distributionthroughout the Lcross-section of the column Vis thereby assured. Thedistribution and 'contact are attained, however, while keeping adefinite classification of the streams at any level. Descending heavyliquid .passes from trough to trough over the upper surfaces of theplates without being -permitted to pass through the perforations, whilethe ascending lighter liquid moves upwardly through the plates withoutmixing with .the collected `liquids in the troughs. Accordingly, `:theproper differences in density are maintained to assure progressivecountercurrent action whereby the descending heavy solvent picks `upincreasing quantities of naphthenic components. and the ascendinglighter solvent picks Aup increasing quantities of parafflniccomponents.

A modified and somewhat simpler form of the invention is shown in Fig.6. Each plate 58 is formed at its upper end with a vertically extendingportion 52 and an inturned portion 54.

The portions 52 of adjacent plates are riveted or welded together and atriangular-shaped trough is thereby formed. The plate 58, as shown inFig. 6, is perforated according to any desired pattern. Louvers, similarto those indicated at 28 in Fig. 4 may be used, and these contribute tocompleteness of contact by promoting turbulence in the cascading streamof heavy solvent. However, plain perforated plates are entirelysatisfactory since the ascending liquid is forced to contact intimatelywith the descending stream.

Ineither form of the invention, the column is highly eil'icient sincethe only portion of the cross-section not available for contact is thattaken up by the troughs themselves, which are of comparatively smallarea. The area available for contact may be as high as of the totalcross-section of thecolumn, as compared with about 65% for Raschig ringcolumns oreother towers of the filled type.

In the construction shown in Fig. 7, the inclined plates are arranged inthe form of conical surfaces co-operatingV with collecting decksv whichtake the place of the .troughs of the modication irst described. Asshown in the drawings, a plurality of decks 18 are arranged atsuccessive levels within the shell, each deck being provided withregularly spaced openings within which cylindrical overilow lsleeves 12are welded. The upper edge of each sleeve may be serrated. Co-operatingwith each sleeve 12 is a coneshaped contact device 14 provided withperforations for promoting contact between the countercurrent fluid. Atthe bottom, each cone is provided with a ring 18 surrounding theoverilow sleeve and suitably attached thereto by bolts or other securingmeans 18. At the top,

.each cone has av small collecting pan 88 sur-l rounded by an'upstanding serrated overow sleeve or Weir 82. A second cone 84 has aringshaped bottom portion 86 fitting within the sleeve 82, and an upperring section 88 secured to the cylindrical overnow sleeve 12 oi' thedeck next above. The apparatus operates in exactly the same fashion asthat shown in Fig. 4, the decks 18 and the collecting pans 88 servingthe same function 'as the troughs 24. The conical contact devices servethe same purpose as the inclined plates. It will be observed that theliquid collecting on each deck 18 is caused to distribute and divide sothat all opportunity for channeling is prevented. 'I'he lighter liquidrising from below passes internally of the lower cone 14 ot each unitand out through the perforations, and thence inwardly through theperforations of vthe upper cone 84, this process being repeated fromdeck to deck. The introduction of liquids is accomplished in the samemanner as inthe arrangement previously described.

A .simple unitary arrangement is shown in Figs. 8 and 9. The entirecolumn is made up of a plurality kof individual units, all of thev typeshown in Fig. 9. Each unit comprises two opposed perforated cones 88 and82, the lower cone 88 having at the top a collecting pan surrounded by asleevev 84, as in the arrangement shown in Fig. 8. The two cones areheld together by a series of braces 86, each welded to the upper coneand the sleeve 84. Except for the braces 86, the cones are identicalwith those shown in Fig. 7.

The bottom ring 88 of the lower cone is immersed in an overflow sectionwhich comprises an overflow sleeve |88 preferably having an up- 'perserrated edge and a.

surrounding hexagonal sleeve |02, the hexagonal sleeve being connectedwith the clindrical sleeve by a horizontal tray portion |04. The bottomring of the cone is secured to and spaced from the sleeve, as indicatedat |06. The units are nested together, as indicated in Fig. 7, thehexagonal sleeves joining together to form in effect a continuous deck.The uppermost units are supported by the units below. It is unnecessaryto attach the hexagonal sleeve portions of adjacent units together,since the column is almost completelyiilled by the joining hexagonalsurfaces. It will be observed that the side portions of the hexagonalsleeve |02 are appreciably higher than the overflow edges of'thecylindrical sleeves |00, in or der to prevent overflow through thejoints. between adjacent units. For this reason, little distribution ofdescending liquid takes place, each column of individual units actingmore or less independently of the others, but adequate contact andclassification are nevertheless obtained, and Ythe construction has theadvantages of simplicity and economy of manufacture.

'Although the invention has been described above as embodied in anapparatus for practicing a liquid extraction process, it is equallysuitable for liquid-to-gas or liquid-to-vapor contact,

`as in scrubbing, washing or rectifying systems.

For example, the column, insubstantialy' identical form to that shown inFig. l, may be used for steam disti1lation. The oil to be distilled isfirst heated and then charged into. the column through the feed pipe I0,steam is introduced by the pipe l2, and reflux vliquid is introduced atI4. Vapors and residual product are withdrawn from the column at i8 andI6, respectively. The vapors ascending the column paas through theplates and contact with descending liquid which passes from trough totrough over the upper surfaces of. the plates. This type of column isespecially suitable for vacuum distillation, since excellent contact maybe promoted without introducing excessive back pressure.

Having thus describedthe invention, what is claimed is:

1. Contact apparatus comprising a column, a plurality of staggered rowsof troughs, and a plurality of rows ofinclined perforated plates, eachattached at its upper end to a trough and immersed at its lower end in atrough of the row next belowcertain of said troughs receiving the lowerends of a plurality of said plates and having a plurality of `downwardlyextending diverging plates attached thereto.

2. Contact apparatus comprising a column, a plurality of staggered rowsof troughs, and a plurality of inclined perforated plates, each attachedat its upper end to a trough and immersed at its lower end in a troughof the row next below, each plate having fins extending outwardly fromthe plate.

3. Liquid extraction apparatus comprising a column, a plurality ofstaggered rows of troughs, a pluralityof inclined perforated plates,each attached at its upper end to a trough and immersed at its lower endin a trough of the row next below, a bottom row of unperforated plates,adjacent plates converging to a narrow opening. means for introducing aliquid into the openings,

and means for introducing a liquid into the uppermost troughs.

4. Liquid extraction apparatus comprising a permost troughs, and meanscolumn, a plurality of staggered rows of troughs, a plurality ofinclined perforated plates, each attached at its upper end to a troughand immersed at its lower end in a trough of the row next below, abottom row of unperforated plates, adjacent plates converging to anarrow opening, means for introducing a liquid into the openings, andmeans for introducing a liquid into the upfor introducing a third liquidinto a mediate point of the column.

5. Contact apparatus comprising a column, a plurality of inclinedperforated plates in the column, means for passing a liquid downwardlyover the upper surfaces of the plates, and means for passing a lighterfluid upwardly through the prforations in the plates, the plates beingprovided with louvers over which the descending liquid cascades.

6. Contact apparatus comprising a column, a

. plurality of contact units in the column, each including an integralplate having an inclined perforated portion and an upper portionoppositely inclined, two of such units being attached together, wherebysaid upper portions form a trough. 'l

7. Contact apparatus comprising a column having a plurality of decks,overflow sleeves in each deck, an lupper perforated conical contactmember depending from each overflow sleeve, a lower conical contactmember surrounding a sleeve of the deck below, and having a collectingpan at the top, and an overflow weir at the edge of the collecting pan.

8. Contact apparatus comprising a column, a plurality of contact units,each consisting of an overflow sleeve and a surrounding polygonalsleeve, a horizontal tray between the sleeves, a

perforated cone upstanding from the overflow 9. Contact apparatuscomprising a column, a plurality of contact units, each consisting lofan v overflow sleeve and a surrounding polygonal sleeve, a horizontaltray between the sleeves, said units being arranged at different levelsin the column, and inclined perforated plates to direct the flow ofliquid from one overflow sleeve to the tray next below.

l0. Contact apparatus comprising a column, a plurality of upwardlyfacing liquid collectors ar.- ranged at each of a number of differentlevels in the column, perforated contact members connected at theirupper ends to said collectors and having inclined surfaces extendingdownwardly toward the collectors at the level next below, said surfacesconverging toward said last-named collectors, means for passing a fluiddownwardly over the surfaces and through the collectors successively,and means for passing a fluid of less density upwardly through theperforations.

11. Contact apparatus comprising a column, a plurality of upwardlyfacing liquid collectors at a number of different levels in the column,perfo- C while passing a fluid ...o

